Christaller’S Central Place Theory


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Christaller’S Central Place Theory

  1. 1. Christaller’s Central Place Theory & Reilly’s Law of Retail Gravitation Valentina Kasperova IB Geography HL Unit: Settlements
  2. 2. Key Terms To Understand <ul><li>Central Place – A settlement, i.e. hamlet, village or market town </li></ul><ul><li>Range – Maximum distance people are prepared to travel for a good or service </li></ul><ul><li>Threshold – Minimum # of people required for a good or service to stay alive </li></ul><ul><li>Low Order Goods – necessities (bread) </li></ul><ul><li>High Order Goods – luxuries (computer) </li></ul><ul><li>Sphere of Influence – Area served and affected by a settlement </li></ul>
  3. 3. Key Assumptions <ul><li>Isotropic Island – area with no variation in relief or climate – flat </li></ul><ul><li>Rational Behavior – assumption that people minimize distance they travel to obtain a good or service </li></ul><ul><li>Even Distribution – population and resources </li></ul><ul><li>All consumers have similar purchasing power </li></ul><ul><li>Transportation costs are equal in all directions and proportional to distance </li></ul>
  4. 4. Arrangement of Central Places <ul><li>Because transport is equally reachable from all distances, market areas are CIRCULAR (Graph C) </li></ul><ul><li>HOWEVER – Circular shape results in un-served or other served market areas (grey areas) </li></ul><ul><li>So, Christaller suggested a HEXAGON shape (Graph D) </li></ul><ul><li>What this suggests : </li></ul><ul><li>- within a given area, there will be fewer high order settlements (towns) in relation to lower order settlements </li></ul><ul><li>- theoretically, settlements are equidistant from each other, higher order settlements further away from each other </li></ul>
  5. 5. Key Principle Threshold & Range Applied <ul><li>In theory – low order goods have a low range and low threshold – less people needed to support it, smaller the distance people are willing to travel </li></ul><ul><li>Low range and low threshold goods are sold in SMALL TOWNS, VILLAGES etc. </li></ul><ul><li>Higher ranges and higher thresholds are sold in LARGE TOWNS </li></ul><ul><li>Same true for services – small town likely to have only general doctor, city a hospital ect. </li></ul>
  6. 6. Intro – Gravitational Models <ul><li>Based on Newton’s law of gravity </li></ul><ul><li>As size of one town increases, so does the movement between them </li></ul><ul><li>However, further apart towns are, the less movement  distance decay </li></ul><ul><li>Models can be used to predict: </li></ul><ul><ul><li>Traffic flows </li></ul></ul><ul><ul><li>Migration between 2 areas </li></ul></ul><ul><li>For our purposes, the concept of breaking points is essential – customer preferences caused by distance </li></ul>
  7. 7. Breaking Points Reilly’s Gravitation Model Applied <ul><li>Gravitational models say: along a route between Point A and Point B there will be a breaking point </li></ul><ul><li>People on left side of the breaking point would shop in Town A, while people on right side of it would shop in Town B </li></ul><ul><li>Operates on assumption that larger towns attract more people  logical behavior </li></ul><ul><li>See attachment for applied examples </li></ul>Explanation of Equation M ab = Distance of breaking point from Town B D ab = Distance between Town A & B P a = Population of Town A P b = Population of Town B
  8. 8. Limitations to Gravity Models <ul><li>Limitations regarding these two assumptions </li></ul><ul><ul><li>Larger the town, the stronger the attraction </li></ul></ul><ul><ul><li>People purchase in a logical way </li></ul></ul><ul><li>Problem is that assumptions do not always have to be true </li></ul><ul><li>Examples: </li></ul><ul><ul><li>Traffic jam on way to larger town, difficult and expensive parking </li></ul></ul><ul><ul><li>Smaller town might have fewer but higher quality shops </li></ul></ul><ul><ul><li>Smaller center might be more comfortable: cleaner, modern, safer </li></ul></ul><ul><ul><li>Some people might have to depend on public transport  difficult </li></ul></ul><ul><li>Basis is assumptions are UNREALISTIC – people aren’t predictable </li></ul>
  9. 9. A Little Visual… Important Note: The borders basically are the breaking points between the settlements
  10. 10. Limitations to CPT <ul><li>Large areas of flat land rarely exist (i.e. Netherlands)  transport is “uneven” </li></ul><ul><li>More types of transport – costs cannot be proportional to distance </li></ul><ul><li>People and wealth are not evenly distributed </li></ul><ul><li>People do not always go to the nearest place </li></ul><ul><li>Purchasing power of people differs </li></ul><ul><li>Perfect competition is unreal – some make more than others </li></ul><ul><li>Shopping habits have changed – People travel larger distances to buy lower order goods (i.e. hypermarkets) </li></ul><ul><li>Theory sees central place as having a particular function  in reality, places have several which change over time </li></ul>
  11. 11. <ul><li>The model is </li></ul><ul><li>COMPLETELY UNREALISTIC </li></ul><ul><li>In today’s world </li></ul>
  12. 12. So Why Do We Have/Use It ... ? <ul><li>Theory has helped geographers and planners to locate new services and plan settlements (i.e. Tesco) </li></ul><ul><li>Valuable information can come from analysis of the model’s results vs. reality  explaining the difference </li></ul><ul><li>NEVER FIT REALITY INTO THE MODEL, FIT THE MODEL INTO REALITY </li></ul>